cognitive processes of avians and primates will be investigated in learning and memory experiments. Three programs of research investigate the strategies and processes of pigeon concept learning, learning basic to accurately performing list memory tasks. One program investigates configural pattern learning of integrating the components of the stimuli as opposed to learning relationships between components, another explores learning with real objects as opposed to object pictures, and a third examines a new procedure of using containers of gravel as stimuli with grain reinforcement buried beneath. Investigations of rhesus monkey list-memory processing focuses on interfering and enhancing effects of previously seen test items, and interference and time-dependent processes responsible for changes in the serial position effects and long-term and short-term memory at different retention intervals. Comparison experiments with human subjects will be conducted with kaleidoscope pattern stimuli.